I've noticed that it seems to be a pattern that's used for other compression/decompression software as well. Sometimes mods I use for games will be uploaded as rars or 7zips (I guess because this stuff gets developed on and for Windows, and tarballs aren't really something people use much there), and the CLI invocations I use to extract them always look off to me, especially the 7zip one: `unrar x` and `7z x`.